staging: wlan-ng: remove unused definitions from p80211types.h

Remove the following unused definitions from p80211types.h:

* struct p80211enum
* struct p80211enumpair
* struct catlistitem declaration and associated function pointer
  typedefs (along with preceding block comment)

Signed-off-by: Tim Collier <osdevtc@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>